Field of the Invention
Embodiments of the present invention generally relate to an apparatus and method for processing substrates.
Description of the Related Art
In the manufacture of integrated circuits and other electronic devices, plasma processes are often used for deposition or etching of various material layers. Plasma processing offers many advantages over thermal processing. For example, plasma enhanced chemical vapor deposition (PECVD) allows deposition processes to be performed at lower temperatures and at higher deposition rates than achievable in analogous thermal processes. Thus, PECVD is advantageous for integrated circuit and flat panel display fabrication with stringent thermal budgets, such as for very large scale or ultra-large scale integrated circuit (VLSI or ULSI) device fabrication.
Plasma processing, such as plasma enhanced chemical vapor deposition (PECVD), is used to deposit materials, such as blanket dielectric films on substrates, such as semiconductor wafers. A challenge for current plasma processing chambers and processes includes controlling critical dimension uniformity during plasma deposition processes. A particular challenge includes substrate center to edge thickness uniformity in films deposited using current plasma processing chambers and techniques.
One problem that has been encountered with plasma processing in integrated circuit fabrication is that devices may become damaged as a result of exposure to non-uniform plasma conditions, such as electric field gradients. The susceptibility or degree of device damage depends on the stage of device fabrication and the specific device design. Devices containing an insulating or dielectric layer deposited on a substrate are susceptible to damage due to charges and/or potential gradients accumulating on the surface of the dielectric layer.
Therefore, there is a need for an improved method and apparatus for plasma processing.